Java·Applied·Geodesy·3D (JAG3D) is one of the most popular open source least-squares software package for geodetic sciences. The Java-based application is distributed under the terms of the GNU General Public License (version 3). JAG3D is designed to combine hybrid terrestrial observations like leveling, directions, distances or vertical angles in a uniform and rigorous mathematical model. Moreover, GNSS baselines that are derived by Global Navigation Satellite System (GNSS) techniques are supported. Some reference projects are the deformation analysis at the Onsala Space Observatory, the rigorous adjustment of laser tracker measurements on the observation level at the electron accelerator S‑DALINAC, or the analysis of local tie networks at fundamental stations to improve global products like the International Terrestrial Reference Frame (ITRF). More information about the least-squares software package JAG3D can be found at software.applied-geodesy.org.

Diagnosis adjustment of planned networks as well as the analysis of existing geodetic networks by means of least-squares adjustment is a principal task in geodetic and metrological sciences such as surveying engineering. The network adjustment yields not only the estimated coordinates and the related fully populated dispersion but also parameters to evaluate the reliability of the network. At the 20th International Course on Engineering Surveying, the principles of geodetic network adjustment were recapitulated within the specific tutorial named network analysis. The conference was held at ETH Zurich from April 11 to 14, 2023. The open source least-squares software package Java·Applied·Geodesy·3D was used to analyse local terrestrial networks, to interpret the adjustment results, and to evaluate network reliability. The principles of Baarda's DIA approach for detection, identification and adaptation of misspecified models were generalised and applied to evaluate network deformations. In complex analysis procedures, the network adjustment is only a cog in the wheel. For that reason, interfaces for data exchange and processing of adjustment results in external applications was addressed.

Together with colleagues from Conservatoire National des Arts et Métiers (CNAM), European Organization for Nuclear Research (CERN), and School of Management and Engineering Vaud (HEIG-VD), we evaluated the compatibility among network adjustment software packages. A detailed description of the procedure and the results was presented at the 5th Joint International Symposium on Deformation Monitoring JISDM 2022.

We compared the results of several geodetic networks using software packages developed by the authors' institutions, namely Compensation de Mesures Topographiques (CoMeT), Logiciel Général de Compensation (LGC), Trinet+ as well as JAG3D. Moreover, we included further commercial software packages such as Columbus, Geolab, Move3 and Star*Net. The networks differ mainly in their extent, i.e. the side length and the height. Whereas the smallest network is about 30 m, the largest network under consideration is about 40 km. The height component varies in a range from 30 m to 2.5 km. The raw data and the obtained results can be found on the official CNAM website.

It is a very important initiative to ensure the quality of adjustment packages. For that reason, the results obtained by JAG3D are available. The largest network extent is about 40 km, and the curvature of the Earth can no longer be neglected. The results obtained by JAG3D differ by about 20 µm for the horizontal and the vertical component w.r.t. the designed values. JAG3D offers comparable results to reputable software packages.

The calibration of measuring equipment is essential in geodesy and metrology. In length metrology, for instance, the calibration enables the traceability of measured values to the SI base unit of the meter. High demands are placed on the standards used to provide reference values in order to ensure conformity with national and international standards and norms such as DIN or ISO. In Germany, the Physikalisch-Technische Bundesanstalt (PTB) as the national metrology institute and supreme technical authority for metrology is responsible for this task.

The calibration of measuring instruments has a certain self-image at least in geodesy. However, the traceability of adjustment algorithms in software packages used is often not taken into account. According to the ISO 10360-6, which deals with the estimation of errors in computing Gaussian associated features, the PTB offers a service to certify metrological adjustment algorithms called Traceability for Computational-Intensive Metrology (TraCIM).

JAG3D's module JUniForm, short for Java·Unified·Form·Fitting, has successfully passed the verification test of the algorithms for computing Gaussian associated features. Several synthetic generated data sets with modeled random and systematic deviations were used to test the implemented algorithms for basic features such as straight line, plane, circle, cylinder, sphere and cone. The resulting maximum permissible errors (MPE) of the estimated parameters were always less than the specified threshold values 0.1 μm and 0.1 μrad.

Proper handling of measured values is complex and requires not only the consideration of calibrated measuring instruments but also the use of reliable adjustment algorithms for a holistic evaluation of the full measuring process. More details can be found in the full TraCIM report.

JAG3D is written in the platform-independent programming language Java and, therefore, the software is runnable at each platform and operation system that provides a Java Runtime Environment (JRE) and the JavaFX. JavaFX is included to the provided bundles. Moreover, the windows download package of JAG3D contains OpenJDK. For that reason, neither Java nor the platform dependent FX extension must be provided by the windows operating system. To run JAG3D on other platforms such as Linux or MacOS, the platform dependent JRE must be installed at the operating system. The JRE can be found for several platforms at Oracles download page or at the OpenJDK-project pages.

JAG3D is a portable least-squares software package - no need to install or uninstall. Just download the latest version, unpack and run. The JAG3D manual is organized by a Wiki. Training videos are compiled in a playlist. Moreover, a support forum is available for technical support.

• Heißelmann, D., Franke, M.: Java·Applied·Geodesy·3D - Evaluation software based on least-squares method for coordinate measuring machines. Traceability for Computational-Intensive Metrology, No. Y4QG8HDUOS76HT5S, Physikalisch-Technische Bundesanstalt, Braunschweig, 2023. 10.5281/zenodo.8217114

• Lösler, M.: Evaluation of Compatibility among Network Adjustment Software - Results from the JAG3D software package. Data-Set, 2023. 10.5281/zenodo.7468733

• Durand, S., Lösler, M., Jones, M., Cattin, P.-H., Guillaume, S., Morel, L.: Quantification of the dependence of the results on several network adjustment applications. In: García-Asenjo, L., Lerma, J. L. (eds.): 5th Joint International Symposium on Deformation Monitoring (JISDM), Editorial Universitat Politècnica de València, Spain, pp. 69-77, 2022. 10.4995/JISDM2022.2022.13671

• Herrmann, C., Lösler, M., Bähr, H.: Comparison of SpatialAnalyzer and Different Adjustment Programs. In: Kutterer, H., Seitz, F., Schmidt, M. (eds.): Proceedings of the 1st International Workshop on the Quality of Geodetic Observation and Monitoring Systems (QuGOMS'11) International Association of Geodesy Symposia, Vol. 140, Springer, pp. 79-84, 2015. DOI: 10.1007/978-3-319-10828-5_12

• Lösler, M., Bähr, H.: Vergleich der Ergebnisse verschiedener Netzausgleichungsprogramme. In: Zippelt, K. (ed.): Vernetzt und ausgeglichen - Festschrift zur Verabschiedung von Prof. Dr.-Ing. habil. Dr.-Ing. E.h. Günter Schmitt, KIT Scientific Publishing, pp. 205-214, 2010. DOI: 10.5445/KSP/1000020074